Michael Levin is a regenerative and developmental biologist at Tufts University in Massachusetts. He has spent most of his career studying how electrical signals travel between cells in the body. Now, he thinks we could use those signals to program our cells to regrow arms, legs, and even faces.

Over at Matter, Cynthia Graber has a terrific essay on Michael Levin's work, and how it fits into the history of regenerative medicine. You won't be able to put it down until you get to the end — which is probably why this article just won the prestigious Institute of Physics journalism prize.

Here's how Graber begins her article:

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A future in which humans regrow lost or diseased body parts feels like a mirage. But why? After all, many species can accomplish the task with ease. A decapitated flatworm, for example, will grow a new head, replete with a new brain. For the first week of their lives, tadpoles can replace lost tails. And the axolotl, or Mexican salamander, has the ability to regenerate everything from its limbs and tail to its spinal cord and skin, all without any evidence of scarring. Even some mammals have limited regenerative abilities: every year, reindeer regrow their shedded antlers. And, in some circumstances, young rats that lose a leg can grow it back.

Humans have a sliver of regenerative capacity, too. If a child experiences a neat slice through the end of his fingertip, that tip will grow back — although the ability disappears sometime around the age of 12. The Greek legend of Prometheus, the god who was cursed to have an eagle peck out his liver each day, only to grow it back overnight, actually contains a grain of physiological truth: if you were to lose part of your liver, it would, in fact, repair itself. With the exception of our skin, it's the only human organ that can do this.

Regenerating a small body part under special circumstances is one thing, but what if we could regrow entire lost limbs? What if we could signal to our bodies to regrow damaged retinal tissue — or even to regrow an entire eye? Michael Levin doesn't think this is an outlandish fantasy. In fact, he thinks he may be on the path to figuring out how to do precisely that.